我需要在我的应用中添加一个搜索栏，但我尝试过的所有教程都无效。因为我希望这个栏能够返回从Excel导入的ListView的值（我以一种活动显示人名的方式应用）。我的ListView是从Excel导入的，而不是在应用内代码中创建的。
也就是说，当我搜索＆＃34; A＆＃34; ListView的所有名称都带有＆＃34; A＆＃34;当我搜索＆＃34; Arn＆＃34;时出现名称包含＆＃34; Arn＆＃34; （例如阿诺德克林顿）。
这是TabelaActivity.java的代码：
package com.akzonobel.malote.tabela;
import com.akzonobel.malote.R;
import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.EditText;
import android.widget.ListView;
public class TabelaActivity extends Activity {
CSVAdapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tabela);
ListView mList = (ListView)findViewById(R.id.mList);
mAdapter = new CSVAdapter(this, -1);
mList.setAdapter(mAdapter);
}
}
这是CSVAdapter.java的代码：
package com.akzonobel.malote.tabela;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import android.content.Context;
import android.graphics.Color;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
public class CSVAdapter extends ArrayAdapter<State>{
Context ctx;
public CSVAdapter(Context context, int textViewResourceId) {
super(context, textViewResourceId);
this.ctx = context;
loadArrayFromFile();
}
@Override
public View getView(final int pos, View convertView, final ViewGroup parent){
TextView mView = (TextView)convertView;
if(null == mView){
mView = new TextView(parent.getContext());
mView.setTextSize(19);
mView.setTextColor(Color.WHITE);
}
mView.setText(getItem(pos).getName());
return mView;
}
private void loadArrayFromFile(){
try {
InputStream is = ctx.getAssets().open("states.csv");
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
String line;
while ((line = reader.readLine()) != null) {
State cur = new State();
cur.setName(line);
this.add(cur);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
这是State.java的代码：
package com.akzonobel.malote.tabela;
public class State {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
我尝试应用此搜索栏：
EditText inputSearch;
inputSearch = (EditText) findViewById(R.id.inputSearch);
inputSearch.addTextChangedListener(new TextWatcher() {
@Override
public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
// When user changed the Text
TabelaActivity.this.mAdapter.getFilter().filter(cs);
}
@Override
public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
int arg3) {
// TODO Auto-generated method stub
}
@Override
public void afterTextChanged(Editable arg0) {
// TODO Auto-generated method stub
}
});
}
搜索栏有效，您可以输入吗？但是当我输入值时......它只是没有返回任何内容，变成空白。有帮助吗？如何使它工作？或者还有另一种简单的方法来制作搜索栏吗？动作棒可以......重要的是它有效。
然后我尝试在CSVAdapter中应用getFilter，但是当我尝试使用带有此getFilter的条时，它会单独崩溃并关闭。
这是我应用的代码getFilter：
private List<State> allModelItemsArray;
private List<State> filteredModelItemsArray;
private Filter filter;
@Override
public Filter getFilter() {
if (filter == null){
filter = new ModelFilter();
}
return filter;
}
private class ModelFilter extends Filter
{
@Override
protected FilterResults performFiltering(CharSequence constraint) {
constraint = constraint.toString().toLowerCase();
FilterResults result = new FilterResults();
if(constraint != null && constraint.toString().length() > 0)
{
ArrayList<State> filteredItems = new ArrayList<State>();
for(int i = 0, l = allModelItemsArray.size(); i < l; i++)
{
State m = allModelItemsArray.get(i);
if(m.getName().toLowerCase().contains(constraint))
filteredItems.add(m);
}
result.count = filteredItems.size();
result.values = filteredItems;
}
else
{
synchronized(this)
{
result.values = allModelItemsArray;
result.count = allModelItemsArray.size();
}
}
return result;
}
@SuppressWarnings("unchecked")
@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
filteredModelItemsArray = (ArrayList<State>)results.values;
notifyDataSetChanged();
clear();
for(int i = 0, l = filteredModelItemsArray.size(); i < l; i++)
add(filteredModelItemsArray.get(i));
notifyDataSetInvalidated();
}
}
当这是激活的getFilter时，除了关闭之外，它还会在LogCat中出现以下错误：
07-13 08:32:52.925: W/Filter(30254): An exception occured during performFiltering()!
07-13 08:32:52.925: W/Filter(30254): java.lang.NullPointerException
07-13 08:32:52.925: W/Filter(30254): at com.akzonobel.malote.tabela.CSVAdapter$ModelFilter.performFiltering(CSVAdapter.java:129)
07-13 08:32:52.925: W/Filter(30254): at android.widget.Filter$RequestHandler.handleMessage(Filter.java:234)
07-13 08:32:52.925: W/Filter(30254): at android.os.Handler.dispatchMessage(Handler.java:99)
07-13 08:32:52.925: W/Filter(30254): at android.os.Looper.loop(Looper.java:137)
07-13 08:32:52.925: W/Filter(30254): at android.os.HandlerThread.run(HandlerThread.java:60)
07-13 08:33:14.856: D/AndroidRuntime(30254): Shutting down VM
07-13 08:33:14.856: W/dalvikvm(30254): threadid=1: thread exiting with uncaught exception (group=0x41101930)
07-13 08:33:14.876: E/AndroidRuntime(30254): FATAL EXCEPTION: main
07-13 08:33:14.876: E/AndroidRuntime(30254): java.lang.NullPointerException
07-13 08:33:14.876: E/AndroidRuntime(30254): at com.akzonobel.malote.tabela.CSVAdapter$ModelFilter.publishResults(CSVAdapter.java:156)
07-13 08:33:14.876: E/AndroidRuntime(30254): at android.widget.Filter$ResultsHandler.handleMessage(Filter.java:282)
07-13 08:33:14.876: E/AndroidRuntime(30254): at android.os.Handler.dispatchMessage(Handler.java:99)
07-13 08:33:14.876: E/AndroidRuntime(30254): at android.os.Looper.loop(Looper.java:137)
07-13 08:33:14.876: E/AndroidRuntime(30254): at android.app.ActivityThread.main(ActivityThread.java:5283)
07-13 08:33:14.876: E/AndroidRuntime(30254): at java.lang.reflect.Method.invokeNative(Native Method)
07-13 08:33:14.876: E/AndroidRuntime(30254): at java.lang.reflect.Method.invoke(Method.java:511)
07-13 08:33:14.876: E/AndroidRuntime(30254): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
07-13 08:33:14.876: E/AndroidRuntime(30254): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
07-13 08:33:14.876: E/AndroidRuntime(30254): at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：0)
向State类添加构造函数：
public State(String name) {
this.name = name;
}
不要使用全局allModelItemsArray和filteredItemsArray，摆脱它们。
然后改变你的performFiltering函数：
@Override
protected FilterResults performFiltering(CharSequence constraint) {
constraint = constraint.toString().toLowerCase();
FilterResults result = new FilterResults();
if(constraint != null && constraint.toString().length() > 0)
{
ArrayList<State> filteredItems = new ArrayList<State>();
for(int i = 0, l = getCount(); i < l; i++)
{
State m = getItem(i);
if(m.getName().toLowerCase().contains(constraint))
filteredItems.add(m);
}
result.count = filteredItems.size();
result.values = filteredItems;
}
else
{
ArrayList<State> allItems = new ArrayList<State>();
for(int i = 0, l = getCount(); i < l; i++)
{
State m = getItem(i);
allItems.add(m);
}
synchronized(this)
{
result.values = allItems;
result.count = allItems.size();
}
}
return result;
}
这样可以更好地解决这个问题。